For the first time, researchers have developed an mRNA vaccine that is 100% effective against a type of bacteria that is lethal to humans, paving the way for effective vaccination against antibiotic-resistant bacteria.
The study, conducted in an animal model, demonstrated that all treated animals were fully protected against the bacteria.
According to the researchers, the new technology can enable rapid development of effective vaccines for bacterial diseases, including diseases caused by antibiotic-resistant bacteria, for example, in case of a new, fast-spreading pandemic.
The study was led by Tel Aviv University’s Dr Edo Kon and Professor Dan Peer, VP for R&D and Head of the Laboratory of Precision Nano-Medicine at the Shmunis School of Biomedicine and Cancer Research, in collaboration with researchers from the Israel Institute for Biological Research: Dr Yinon Levy, Uri Elia, Dr Emanuelle Mamroud, and Dr Ofer Cohen. The study’s results were published in the journal Science Advances.
Dr Kon explains: “So far mRNA vaccines, such as the Covid-19 vaccines familiar to all of us, were assumed to be effective against viruses but not against bacteria. The great advantage of these vaccines, in addition to their effectiveness, is the ability to develop them very quickly: once the genetic sequence of the virus SARS-CoV2 (Covid-19) was published, it took only 63 days to begin the first clinical trial.
“However, until now scientists believed that mRNA vaccines against bacteria were biologically undoable. In our study, we proved that it is in fact possible to develop 100%-effective mRNA vaccines for deadly bacteria.”
Full protection with just one dose
Researchers have previously tried to synthesise bacterial proteins in human cells, but exposure to these proteins resulted in low antibodies and a general lack of protective immune effect. Even though the proteins produced in the bacteria are essentially identical to those synthesised in the lab, those produced in human cells undergo significant changes, like the addition of sugars, when secreted from the human cell.
To address this problem, the scientists developed methods to secrete the bacterial proteins while bypassing the classical secretion pathways. The result was a significant immune response, with the immune system identifying the proteins in the vaccine as immunogenic bacterial proteins.
To enhance the bacterial protein’s stability and ensure that it does not disintegrate too quickly inside the body, they buttressed it with a section of human protein.
Professor Peer added: “There are many pathogenic bacteria for which we have no vaccines. Moreover, due to excessive use of antibiotics over the last few decades, many bacteria have developed resistance to antibiotics, reducing the effectiveness of these important drugs. Consequently, antibiotic-resistant bacteria already pose a real threat to human health worldwide.
“The ability to provide full protection with just one dose is crucial for protection against future outbreaks of fast-spreading bacterial pandemics. If tomorrow we face some kind of bacterial pandemic, our study will provide a pathway for quickly developing safe and effective mRNA vaccines.”
Image shows: Dr Edo Kon.